It kind of makes sense, since the fluoride in our toothpastes disturbs the normal oral bacterial and fungal fauna, which is allowed to restore when you go off fluoride. Some of us believe EC has a strong link with a fungal infection (Candida). However, it can also be a risk because "bad" bacteria in this case might be allowed to grow excessively which can damage teeth and gums. Also, recently I saw a TV commercial about a pill you can take to partially restore the normal, healthy balance between 'good' and 'bad' organisms -- the pill is intended for people with bad breath.